To　investigate　the　relationship　between　the　changes　in　the　number　and　function　of　the　late　endothelial　progenitor　cells　(EPC)　in　peripheral　blood　and　the　carotid　artery　stenosis.　60　cases　were　selected　and　were　divided　into　the　carotid　artery　stenosis　group　of　40　cases　(mild　stenosis　in　20　cases,　moderate/severe　stenosis　in　20　cases),　normal　control　group　of　20　cases　with　the　global　cerebral　angiography.　Extracted　the　blood　of　femoral　artery　from　the　patients　during　the　global　cerebral　angiography,　mononuclear　cells　were　isolated　from　peripheral　blood　by　density-gradient　centrifugation　and　were　cultured　to　21　days　when　they　were　identified　as　late　endothelial　progenitor　cells,　counted　the　colony　numbers　of　late　EPC.　Then　the　proliferation,　migration　and　adherentce　ability　of　late　EPC　were　determined　by　the　MTT　assay,　modified　Boyden　and　the　HFN　culturing　plates.　The　amount　of　the　late　EPC　colonies(34.30　+/-　A　4.90,　25.38　+/-　A　6.33)　were　significantly　reduced　in　the　patients　with　carotid　artery　stenosis　compared　with　the　control　group　(46.00　+/-　A　5.64)　(P　＜　0.05);　the　function　of　proliferation,　migration,　adhesion　of　the　late　EPC　in　patiens　with　cerebral　artery　stenosis　were　significantly　lower　(P　＜　0.05),　the　number　and　function　of　late　EPC　decreased　with　the　worsening　of　vascular　stenosis　(P　＜　0.05).　The　number　of　EPC　in　peripheral　blood　of　patients　with　the　carotid　artery　stenosis　decreased,　the　function　was　impaired,　and　number　and　function　changes　of　late　EPC　were　negatively　correlated　with　the　degree　of　carotid　artery　stenosis.